Adjustable quick-release mechanism for print drum



Oct. 17, 1967 J. A.ALTONJ| ET AL 3,347,159'

ADJUSTABLE QUICKRELEASE MECHANISM FOR PRINT DRUM Filed Dec. 31, 1964 1 5 Sheets-Sheet 1 lNV ORS ATTORNEY J. A. ALTONJI ET AL 'ADJUSTABLE QUICK-RELEASE MECHANISM'FOR PRINT DRUM 3 Sheets-Sheet 2 Filed Dec.

' INVEN TORS JOHN/1,41 TOM/7 Jmw/ 9% t44/A/v4 BY ATTORNEY ADJUSTABLE QUICK-RELEASE MECHANISM FOR PRINT DRUM Oct. 17, 1967 Y J, ALTONJI ET AL A 3 Sheets-Sheet 5 Filed Dec.

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- ATTORNEY 'ations.

United States Patent Office 3,347,159 Patented Oct. 17, 1967 ADJUSTABLE QUICK-RELEASE MECHANISM FOR PRINT DRUM John A. Altonji, Syosset, and Joseph G. Vaiana, Levittown, N.Y., assignors to Potter Instrument Company, Inc., Plainview, N .Y., a corporation of New York Filed Dec. 31, 1964, Ser. No. 422,621 4 Claims. (Cl. 101-93) This invention, generally, relates to high speed printers for computers and, more particularly, to an improved mechanism for detachably mounting the printing drum of a high speed printer in an adjustable and easily releas able manner.

High speed printers, of course, are known to the art. In such printers, a massive, rapidly rotating drum is utilized to carry type characters in a predetermined pattern around its surface. A printing hammer module, or modules,'extend along a line parallel to the axis of the drum positioning a plurality of printing hammers close to the periphery of the drum. A web of paper and carbon paper is fed through a gap between the hammers and the drum so that upon actuation of a selected hammer, the web is driven against the particular type character on the drum that is opposite the hammer at that instant.

From time to time, it is necessary to remove the drum for various reasons, such as for cleaning or to exchange the drum for one with new or different characters. With the drums known to the art, such removal and replacement has been relatively complex and time consuming, disabling not only the printer, but associated equipment.

High speed printers of the type with which the present invention relates must achieve high speeds primarily because-the input is supplied by computer apparatus at relatively high speeds. The high speeds which are attained require that the frame portions of the printer apparatus be substantially rugged, massive and arranged rigidly relative to component parts thereof to avoid the development of-vibrations which would affect the printing operation.

In such printer apparatus, it is necessary to have one portion of the frame attached to pivot away from another frame portion for such purposes as access to inner component parts for repairs, inserting paper supplies,

etc. It is essential, therefore, that a latch assembly for attaching any movable frame portion in a printing position'be at least as rugged as the-frame itself, and more importantly, it is essential that such a latch assembly return the movable frame portion to an accurately predetermined position.

Therefore, it is one object of this invention to provide a quick release mechanism to attach a print drum in a printing position on a high speed printer.

A further object of the invention is to provide a quick release mechanism for adjustably securing a print drum within a high speed printer in a positive, accurately predetermined relationship.

In many instances, variation in print density occurs with a change of paper thickness, and it is desirable to control the gap spacing to compensate for such vari- Accordingly,.it is another object of this invention to provide a print drum mounting mechanism capable of gap compensation control in simple and efficient manner.

to receive the respective ends of the print drum shaft so that the center line of the shaft is offset from the center of rotation of the bearing blocks. An arm is coupled at one end to one bearing block, and the other end of the arm has a lock to retain the arm in a desired pivotal position.

Thus, for removal or insertion of the drum, the arm and the bearing blocks are rotated until the slots therein are aligned with the passageway in the mounting brackets, whereupon the drum can be removed by sliding the ends of the shaft through the respective passageways.

When the drum is mounted for use, the arm is pivoted so that the slots in the bearing blocks are displaced from the passageway in the mounting brackets to lock the drum shaft positively within the mounting brackets. The end of the arm is provided with an eccentric cam for engaging a fixed stop so that rotation of the cam provides precise pivotal positioning of the end of the arm, thereby to adjust gap clearance for variation in the printing web material.

Having briefly described this invention, it will be described in greater detail in the following portions of the specification, which may best be understood by reference to the accompanying figures, in which:

FIG. 1 is an exploded perspective view obliquely from the rear of a print drum mounting mehanism in accordance with the present invention;

FIG. 2 is an elevation view of a printer constructed in accordance with the present invention; 30

FIG. 3 is a partial top view of the printer shown in FIG. 2;

FIG. 4 is a cross sectional view taken along the line 4-4 of FIG. 2;

FIG. 5 is a cross sectional view taken along the line 5-5 of FIG. 4; and

FIG. 6 is a cross sectional view taken along the line 6-6 of FIG. 4.

In the drawings, a print drum 10, indicated in phantom lines, is mounted rotatably by suitable bearings 11a and 11b on a shaft 12, the opposite ends 13 and 14 of which are flattened to form blade-like sections. This is best seen in FIGS. 1 and 6.

The numerals 15 and 16 identify, respectively, sides of a printer frame, and mounting brackets 17 and 18 are fixedly attached to the sides 15 and 16 by any suitable means such as, for example, a plurality of screws similar to the single screws 19 and 20 in FIG. 4. Each mounting bracket 17 and 18 has a cylindrical bore 21 and 22, respectively, and a passageway 23 and 24 communicates externally of the mounting brackets from each respective bore 21 and 22.

Two cylindrical bearing blocks 25 and 26 fit slidably and pivotally within the respective bores 21 and 22, and a radially extending slot 27 and 28 in each block 25 and 26 communicates with the respective passageways 23 and 24 when the bearing blocks are in one pivotal position. The depth of each slot 27 and 28 is determined precisely so that the axial center line of the shaft 12 will be offset from the axial center line of the bearing blocks 25 and 26 when the blade-line ends 13 and 14 are inserted fully. The Width of each slot 27 and 28 must be formed to receive the blade-line ends 13 and 14 of the shaft 12 in close fitting, sliding relationship, as illustrated by the numerals 29 and 30 in FIG. 6.

The print drum 10 maybe removed simply and quickly when the bearing blocks 25 and 26 are pivoted to align the slots 27 and 28 with the passageways 23 and 24. A more detailed description of this type of bearing block support for a high speed printer is set forth in US. Patent No. 3,118,369 of Carmine J. Antonucci, which is assigned to the assignee of this invention.

A disc 35 is rotatably mounted over the shoulder 36 of the pin 33 and has an enlarged opening 37 permitting rotation about a shaft 38 extending from a shoulder 39 on a knurled knob 40. The shaft 38 is rotatable within an opening in the side 15 of the printer frame so that when the knob 40 is tightened by screwing it onto the pin 33, the shoulder 39 looks the disc 35 firmly in place.

Another knurled knob 41 has a threaded part 42 for sliding readily through an arcuate slot 43 in the end 32 of the arm 31 for threading into an opening 44 in the disc 35.

It is important that the opening in the disc 35 for receiving the shoulder 36 be off-center so that the periphcry of the disc 35 will act as a cam when it is pivoted.

A set screw stop 45 is threaded into a shoulder 46 on the side 15 of the frame against which the disc 35 will bear, as best seen in FIG. 2, when the print drum 10 is in operating position. In this operating position, the axial center line, in FIG. 2, of the print drum is indicated by the point 47, and the axial center line for both of the bearing blocks 25 and 26 is indicated by the point 48.

Therefore, with the print drum 10 in operating position, a gap is formed at a point indicated by the numeral 49, in FIG. 2, between the drum and a plurality of print hammers 50 to permit a web,indicated by the numeral 56, to pass through. In the event multiple copies are desired to be printed, the thickness of the web 56 will vary. A rough adjustment for the gap 49 is provided by turning the set screw stop 45, but a quicker and precalibrated adjustment is provided by the disc 35, in accordance with the invention.

Referring to FIG. particularly, two sketches are indicated by (a) and (b) depicting the disc 35 bearing against the set screw stop 45 in two different rotational positions for the disc 35.

In FIG. 5(a), the axis 47 of the drum lies in the same vertical plane as the axis 48 of the bearing blocks 25 and 26. However, in FIG. 5(b), the disc 35 has been rotated 90 moving the axis 47 further from the set screw stop 45 due to the cam action of the disc 35, and thus, the gap 49 between the drum 10 and the print hammers 50 is increased.

To adjust the gap 49 quickly, in accordance with the invention, the knurled knob 41 is loosened and the threaded part 42 is moved arcuately in the slot 43. When the desired gap is obtained, the knob 41 is tightened. This may be calibrated, if desired, by a suitable index on the periphery of the disc 35. For removing the drum 10, the knurled knob 40 is loosened, and the shaft 38 is moved in an arcuate slot 51 in the side in the direction of the arrows 52 in FIG. 2 to a point where the slot 27 lines up with the passageway 23.

It may be seen that the bearing blocks 25 and 26 are retained in rotatable position by two set screws 53 and 54 each having a small knob to ride within a peripheral groove in each bearing block.

In operation, the drum 10 is rotated at high speeds by means of a suitable belt wrapped around a pulley 55 fixed to the drum 10. In removing the drum 10 from the frame 15, after the bearing blocks 25 and 26 are rotated by means of arm 31 to a position when the slots 27 and 28 in the bearing blocks 25 and 26 are aligned with the passageways 23 and 24, respectively, the drum 10 may be grasped and removed by hand from the frame, for example.

In order to adjust the gap 49, the arm 31 is moved a certain amount along the slot 51, after the knob 41 has been loosened in the manner previously explained. As may be seen readily by an inspection of FIGS. 2 and 6, as the bearing blocks 25 and 26 rotate about their axes 48, the drum axis 47 moves relative to the print hammer 50 owing to the fact that the axes 48 of the bearing blocks is off-set from the axis 47 of the drum 10.

Inasmuch as the invention herein described is susceptible to many variations by one skilled in the art, all such variations are intended to be included within the scope of the invention as set forth in the claims appended hereto.

What is claimed is:

1. A high speed printer comprising:

a frame,

a printing hammer module mounted in said frame in a predetermined position, a print drum mounted rotatably in said frame adjacent to said printing hammer module for rotation about a first axis,

said printing drum being rotatably mounted on a shaft a second axis to receive respectively each, end of.

said shaft, said bearing blocks holding said shaft with said first axis maintained displaced from said second axis within a predetermined range of rotation of said bearing blocks, and means to rotate said bearing blocks within said predetermined range to adjusta-bly position said printing drum with respect to said printing hammer module.

2. A high speed printer in accordance with claim 1, in which said bearing blocks include slots and said frame includes passageways which may be aligned with said slots in order to permit removal of said print drum.

3. A high speed printer in accordance with claim 2 in which said means for rotating said bearing blocks comprises a lever, one end of said lever being coupled to one of said bearing blocks, and the other end of said lever being movable along a predetermined are for adjustment of the clearance between the drum and the printing hammer module.-

4. A high speed printer in accordance with claim 3, which includes an eccentric cam mounted on the other end of said \lever, a stop fixedly positioned on said frame, and means for rotating said cam to move said end of said lever over a predetermined are, for adjustment of the clearance between said drumand said hammer module.

References Cited UNITED STATES PATENTS 1,906,304 5/1933 Barrett 197-149 X 2,804,015 8/1957 Brougham 101-247 2,839,176 6/1958 Metzner et al. 197-149 3,023,699 3/1962 MacArthur 101-375 3,118,369 1/1964 Antonncci 101-93 3,154,184 10/1964 Gallant et al. 197-149 3,155,032 11/1964 Antonncci 101-93 3,164,083 1/1965 Irvine 101-93 B. PENN, Primary Examiner, 

1. A HIGH SPEED PRINTER COMPRISING: A FRAME, A PRINTING HAMMER MODULE MOUNTED IN SAID FRAME IN A PREDETERMINED POSITION, A PRINT DRUM MOUNTED ROTATABLY IN SAID FRAME ADJACENT TO SAID PRINTING HAMMER MODULE FOR ROTATION ABOUT A FIRST AXIS, SAID PRINTING DRUM BEING ROTATABLY MOUNTED ON A SHAFT EXTENDING ALONG SAID FIRST AXIS AND EXTENDING FROM EACH END OF SAID DRUM, BEARING BLOCKS ROTATABLY MOUNTED IN SAID FRAME ABOUT A SECOND AXIS TO RECEIVE RESPECTIVELY EACH END OF SAID SHAFT, SAID BEARING BLOCKS HOLDING SAID SHAFT WITH SAID FIRST AXIS MAINTAINED DISPLACED FROM SAID SECOND AXIS WITHIN A PREDETERMINED RANGE OF ROTATION OF SAID BEARING BLOCKS, AND MEANS TO ROTATE SAID BEARING BLOCKS WITHIN SAID PREDETERMINED RANGE TO ADJUSTABLY POSITION SAID PRINTING DRUM WITH RESPECT TO SAID PRINTING HAMMER MODULE. 